Active matrix organic light-emitting diode (AMOLED) displays are among the hot spots in today's flat panel display research. The organic light-emitting diode (OLED) has advantages such as low energy consumption, low production cost, being self-luminous, a wide viewing angle and a fast response speed, as compared with the liquid crystal display (LCD). At present, OLED displays are starting to replace traditional LCD displays in the fields of mobile phone, personal digital assistant (PDA), digital camera and the like. Pixel driving circuit design is the core technology of an AMOLED display, and is of important research significance.